If not incompetent, they AND the customer did not do their due diligence to completely understand what the customer wanted. The customer absolutely must know what he wants and provide that information to the shop.
If I take a block to the machinist and tell him to bore out my block a lot so I can fit bigger pistons, I can't complain if he bores them 0.040 when I wanted 0.050 because that's what pistons I picked up on craigslist are. Now, the machinist failing to ask for that information will quickly put him out of business because that angry customer will both complain on forums and Yelp because he's a dumbass, whether it is deserved or not.
As a customer it is your duty to know exactly what you want then go hunt that down. If you fail to properly plan your build, that is on you.
